The present invention relates to an apparatus and method for driving nails. In particular, it relates to a device for driving a plurality of nails according to a preselected pattern.
Devices which automatically drive a preselected pattern of nails into an arrangement of components are known. One such device is an automated pallet nailer. The known pallet nailer includes a carriage for retaining an arrangement of wood boards and blocks to be nailed together, retaining brackets for gripping the arrangement and holding the arrangement on the carriage during nailing, a nailing station for driving a plurality of nails into an upper surface of the arrangement, a conveyor for driving the carriage under a nailing station, and a computer for controlling the sequence and timing of the various operating steps.
Devices known in the art do not provide means for automatically moving the nailing heads in a direction transverse to the direction of travel of the carriage during nailing to an infinitely variable number of positions. Known devices therefore cannot be programmed to deliver nailing patterns which are other than linear in a direction of travel of the carriage from a single nailing head. Known devices also cannot be programmed to change from one nailing pattern applied to one pallet surface to another if the different patterns require changes in transverse positioning of the heads between nailing operations other than to a finite number of discrete positions.
Block pallet nailers known in the art provide two to three nailing heads for each board comprising the surface being nailed. Current machine designs require the operator to arrange the components such that the boards comprising the top surface of the arrangement to be nailed are positioned with a long dimension in a direction of travel of the carriage. Since there are almost always more top boards than lower support boards or "stringer boards", which are perpendicular to the top boards, this nailing arrangement typically requires a large number of nailing heads. When nailing conventional double sided pallets, the number of boards comprising an upper surface is seven. Therefore, fourteen or twenty-one nailing heads are required, depending upon board size, for operating a known pallet nailer when producing such a product. Since the amount of downtime due to equipment malfunction is directly related to the number of nailing heads, it would be desirable to reduce the number of nailing heads in a pallet nailing machine.